As a conventional method for evaluating a photosynthetic sample contained in an evaluation sample (methods for evaluating a degree of impact of an environmental factor (such as a chemical substance) having impact on growth of a living organism, etc.), there is a method for ecological risk evaluation of a chemical substance, with which an evaluation is made using growth of cells of a plant, algae, or other plant origin. A most general type of such an evaluation method is an algae growth inhibition test, which is a bioassay for ecological risk evaluation of a chemical substance. The algae growth inhibition test is conducted in accordance with guidelines of the Organization of Economic Co-operation and Development (OECD). In the algae growth inhibition test, algae is cultured for 72 hours in a state of being exposed to a chemical substance and growth inhibition is measured to evaluate harmful properties of the chemical substance.
However, with the algae growth inhibition test, because a growth ability of a living organism is subject to testing, operations are complicated and a long time of 72 hours is required to obtain test results. Meanwhile, there is, for example, a method such as described in Patent Document 1 where a delayed luminescence, emitted from an algae, is measured to evaluate an environmental impact of a chemical substance. Delayed luminescence is phenomenon where, upon illumination of light on a living organism with a photosynthetic function, emission of fluorescence occurs from a photosynthetic pigment due to energy of the light. By this method, an environmental impact of a chemical substance can be evaluated in a short time.
Also, in Non-Patent Documents 1 and 2 is described a derivation of a luminescence model equation from reaction equations of a photosynthetic electron transport system for describing emission of delayed luminescence from a photosystem II, a plastoquinone pool, and a photosystem I, which are principal reaction sites of the photosynthetic electron transport system. The model equation is constituted of a plurality of exponential functions. These non-patent documents disclose that the model equation exhibits a shape close to experimental results.
A luminescence model equation, constituted of a plurality of exponential functions, is also disclosed in Non-Patent Document 3. It is also described here that by substituting suitable factors into the model equation, variations similar to experimental results are obtained.
Patent Document 1: International Patent Publication No. 2005/062027 Pamphlet
Non-Patent Document 1: Von G. Kretsch and V. Gerhardt, “Numerical analysis of delayed fluorescence kinetics of algae,” F. Schweizerbart'sche Verlagsbuchhandlung, 1987, 29, pp. 47-54.
Non-Patent Document 2: Hans Krause, Gerd Kretsch, and Volkmar Gerhardt, “DIFFERENTIAL EQUATIONS FOR DELAYED FLUORESCENCE KINETICS IN LIVING PLANTS,” Journal of Luminescence, Elsevier Science Publishers B. V., 1984, 31 & 32 (1984), pp. 885-887.
Non-Patent Document 3: Werner Schmidt and Horst Senger, “Long-term delayed luminescence in Scenesdesmus obliquus II Influence of exogenous factors,” Biochimica et Biophysica Acta, Elsevier Science Publishers, 1987, 891 (1987), pp. 22-27.